20217143 has 4 divisors (see below), whose sum is σ = 20245680. Its totient is φ = 20188608.

The previous prime is 20217137. The next prime is 20217163. The reversal of 20217143 is 34171202.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 20217143 - 2¹² = 20213047 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20217103) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 13178 + ... + 14631.

It is an arithmetic number, because the mean of its divisors is an integer number (5061420).

Almost surely, 2^20217143 is an apocalyptic number.

20217143 is a deficient number, since it is larger than the sum of its proper divisors (28537).

20217143 is an equidigital number, since it uses as much as digits as its factorization.

20217143 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 28536.

The product of its (nonzero) digits is 336, while the sum is 20.

The square root of 20217143 is about 4496.3477401109. The cubic root of 20217143 is about 272.4205890425.

Adding to 20217143 its reverse (34171202), we get a palindrome (54388345).

The spelling of 20217143 in words is "twenty million, two hundred seventeen thousand, one hundred forty-three".